Dynamo-electric machinery.



PATENTED AUG. 18, 1903'...

H. QHITLTYN DYNAMO ELECTRIC MACHINERY. urmommm TILED NOV'., 14, 1902.

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UNITED STATES Patented August 18, 1903.

HENRY CHITTY, OF SOUTH NORWOOD, ENGLAND.

DYNAMO-ELECTRIC MACHINERY.

SPECIFICATION forming part of Letters Patent No. 73 6,362, dated August 18, 1903.

Application filed November 14, 1902. Serial No. 131,293. (No model.)

To all whmn it may concern:

Be it known that I, HENRY CHITTY, a subject of the King of Great Britain, residing at Itala, 2 Clifton road, South N orwood, in the county of Surrey, England have invented a new and useful Improvement in Dynamo- Electric Machinery, of which the following is a specification.

This invention relates to dynamoelectric machines, and has for its object to provide improved means for Ventilating such machines.

The invention is particularly applicable to that type of machine in which both members are provided with ventilation passages or ducts in planes parallel with the direction of rotation, said passages being arranged to register. The rate of heat dissipation, although determined in a measure by the extent of the radiating-surface, depends to a very great extent upon the quantity of air passed through the ventilating-ducts in a given time. In order, therefore, to secure the most effective cooling of the machine, it is essential that the fullest provision is made for the free escape of the air discharged from the openings in the periphery of the revolving armature.

Since usually about two-thirds of the armature-surface is covered by the pole-faces, it is of importance so to construct the polepieces that every facility is afforded for the transmission of air through the ventilatingpassages with the least possible obstruction or resistance. Accordingly I form each of the pole-pieces with a division or passage preferably radial and parallel to the axis of rotation of the armature. Such division or passage may be carried partly through the polepiece or it may with advantage be made to completely divide the polepiece into two parts.

In order that my invention may be clearly understood, I will proceed to describe by the aid of the accompanying drawings how the same may be carried into practice. 7

Figure 1 is a side elevation of a portion of a multipolar machine, part being in section. Fig. 2 is a face View, partlyin section, of one of the pole-pieces; and Fig. 3 is a section on the line III III, Fig. 1.

The machine illustrated is of the six-pole type with a slotted armature, the core of which is indicated at 1. The armature is provided with ventilation-passages 2, located in planes perpendicular to the axis, and the pole-pieces 3 of the field-magnet are provided with corresponding ventilation-passages 4;. For the purpose of providing for the free escape of the air discharged through the Ventilatingpassages 2" and a the pole-pieces are, according to the present invention, provided with a passage or opening 5, preferablyflaring and communicating with all the ventilation-passages 4. By this means the air emitted from the armature after passing through a portion of the pole-piece is free to escape into the atmosphere through a passage of comparatively large sectional area, and the friction due to its passage through the comparatively narrow ventilation-channels heretofore employed is considerably lessened. In the drawings the passage 5 is shown as being carried completely through the pole-piece, dividing this into two parts, and the ventilationpassages 4 are of triangular form, as shown in the sectional part of Fig. 1. These ventilation-passages are arranged to communicate with the passage 5 at a point where the sectional area of said passage is equal to or exceeds the effective area of all the ventilation-passages at the polar face. The passage 5 need not, however, divide the pole-piece, it being sufficient if the effective area of the air-passage continuously increases from the polar face out ward. The ventilation-passages at may also be carried completely through the pole-pieces if desired.

The transverse passage 5 need not be symmetrically arranged with reference to the pole-piece, as shown, but may be located at any suitable place. It is preferably made flaring or taper, but this is not essential, and my invention includes variations in the shape of such passage. I wish it to be also understood that the invention is not necessarily limited in its application to dynamo-electric machines in which either or both of the mem bers are provided with ventilation ducts or channels in a plane parallel with the direction of rotation.

The machine shown in the drawings is of the six-pole type, and both armature and field are preferably formed of laminae, as indicated in the upper part of Fig. 3, portions of these laminae being cut away at suitable places to form the ventilation passages. My invenbination of two members which have a rotary movement relatively to each other, one of said members surrounding the other member and being provided with pole-pieces each of which is divided by a flaring passage the narrowest part of which is located in the polar face and which communicates with ventilation passages extending in planes substantially perpendicular with the axis of the machine.

2. In a dynamo-electric machine, the combination of two members which have a rotary movement relatively to each other, one of said members being composed of laminae shaped to form pole-pieces, portions of some of said laminae being cut away so as to form ventilating-passages opening onto the polar face,

each ventilating-passage communicating with a transverse passage also formed by cutting away portions of adjacent laminae.

3. In a dynamo electric machine, the combination of two members which have a rotary movement relatively to each other, both of said members being provided with ventilation-passages in planes perpendicular to the axis of rotation,and one of said members having polepieces provided with a transverse passage communicating with the ventilating passages therein.

4. In a dynamo-electric machine, the combination of two members which have a rotary movement relatively to each other, one of said members being provided with ventilation-passages in planes parallel with the direction of rotation, the other member having pole-pieces each of which is provided with a ventilationpassage parallel with the axis of rotation.

In testimony whereof I have signed my name to this specification, in the presence of two subscribing witnesses, this 4th day of November, 1902.

HENRY CIIITTY.

lVitnesses:

F. W. LE TALL, A. S. OACHEMAILLE. 

